BOGOTA, Colombia -- A survey of Colombia's coca fields sponsored
by a U.N. agency suggests they are far larger than previously believed
-- one-third the size of Miami-Dade County. But U.S. officials say they
doubt the estimate because of the methods used.

The survey by the U.N. Drug Control Program, or UNDCP, estimated
Colombia's coca fields at 402,610 acres, compared to Miami-Dade's 1.3 million
acres, based on images taken Aug. 31 from one U.S. and two French commercial
satellites. The results were made public in mid-May, provoking a debate
over the efficacy of U.S. counter-narcotics policies.

The total is enough to make 800 to 900 tons of cocaine -- U.S.
consumption is estimated at 269 tons a year -- but represents only a 2
percent growth from the results of a mid-1999 trial run of the satellites
hired for the project.

``In other words, the year 2000 allows us to see a trend toward
the stabilization or braking in the growth of the cultivation,'' said the
Colombian government's National Narcotics Council when it released the
study.

U.N. and U.S. officials cautioned that their figures cannot be
compared to the latest, much smaller U.S. estimates announced in March
because of the different
technology used and times involved.

Washington's assessments of coca cultivation are crafted by CIA
analysts from data gathered not only by satellites, but also by surveillance
aircraft and other methods during the last three months of each year --
as opposed to the one-day blanket coverage by satellites used by the U.N.
study.

``This report says only that the area is very large,'' said Klaus
Nyholm, head of the U.N. Drug Control Program's Bogotá office.

LIVELY DEBATE

But the report has already added to a heated debate in Washington
over U.S. counter-drug policies, which rely heavily on increased military
aid to Colombia and the aerial spraying of coca fields with a chemical
weedkiller.

``This means we bit off more coca than we can chew,'' said Sanho
Tree, director of the Drug Policy Project at the Institute for Policy Studies,
a liberal think-tank in
Washington. ``The options now are either to dramatically escalate
this war or face the reality that this is a war we cannot win.''

Countered Stephen Johnson, drug policy analyst with the conservative
Heritage Foundation in Washington: ``This is a clarion call that we need
to do more on the supply side of the problem.''

The latest U.S. estimate of Colombia's coca acreage pegged the
year 2000 total at 326,000 acres, an 11 percent increase over 1999. Previous
U.S. estimates had put growth from 1998 to 1999 at 20 percent.

Rand Beers, assistant secretary of state for international narcotics
and law enforcement, said in Washington recently that it would be premature
to assume the U.N.
figures pointed to a failure of the U.S. aerial spraying in Colombia
because of the different methodology.

A $1.3 billion U.S. aid package approved last summer for the counter-narcotics
and nation-building effort known as Plan Colombia included $115 million
for stepped up aerial spraying.

``It may too early to say that Plan Colombia is not working .
. . but the U.N. study certainly shows the problem is far bigger than we
thought,'' said Adam Isacson of the liberal Center for International Policy
in Washington.

VARYING ESTIMATES

UNDCP agreed in 1999 to finance the satellite surveys because
of the huge gaps between the CIA and Colombian police estimates over the
years, with the CIA figures usually more conservative than the Colombian
figures.

Colombian police officials said that while the UNDCP figures on
size and growth rates cannot be compared to the U.S. or Colombian police
estimates, they do provide interesting insights.

The UNDCP-estimated increase of 7,410 acres between the trial
run in mid-1999 and the survey Aug. 31 came despite the 143,000 acres that
police reported spraying -- and eradicating -- in all of last year, they
noted.

And the UNDCP's higher acreage estimate should cast doubt on U.S.
estimates of the percentage of Colombian cocaine exports intercepted by
U.S. agencies -- in effect, their ``success rate'' in the war on drugs.

Further complicating the picture, Colombia's military and police
found a huge increase in coca acreage when they launched an intense spraying
campaign Dec. 19 in the southern state of Putumayo, believed to be home
to about 50 percent of the country's coca production.

``In one area we had estimated 6,175 acres, but found 14,820 acres''
Gen. Mario Montoya, the region's top military commander, told The Herald
in a recent interview. ``And it was the same story everywhere we went.''

EXPANDED SPRAYING

The seven-week air eradication campaign, the first effort financed
from the $115 million in U.S. aid, sprayed some 74,000 acres with glyphosate,
a weed killer sold under the trademark of Roundup.

Police reported spraying an additional 94,000 acres in the first
four months of this year, and U.S. Ambassador Anne Patterson said recently
that she expected this year's total to hit 198,000 acres.

U.S. officials have steadily cautioned that the aerial spraying
campaign will need time to gear up.

The $115 million included money to buy five new crop dusters,
which have yet to arrive in Colombia.

``It will take until 2003 before we get ahead of the [new plantings]
curve,'' one government narcotics analyst in Washington said.